The invention relates to a piezoelectric element for converting pressure signals into electrical signals and vice versa, according to the preamble of the independent claim as well as to an oscillation transducer with a piezolectric element.
From DE 40 29 972 there is known a piezoelement which is designed as an ultrasound tranducer and which consists of several layers of a porous piezoceramic arranged over one another, with electrodes connected therebetween. Each layer of the porous piezoceramic is manufactured by pulling a plastic foil through a supply vessel which contains a ceramic slip mixed with a pearl polymeride. The foil stack is subsequently pressed and fired. Within each layer the porous piezoceramic with respect to the porosity has a gradient, wherein on the border surfaces there is present a minimal porosity for improving the contact to the electrodes.
Oscillation transducers are used for the most different of applications, they may be used in microphones, in particular contact microphones for the purpose of news transmission, in acceleration recorders, apparatus for auscultative diagnosis, seismic ground examination or likewise, in safety signal systems and other installations.
From EP 0 515 521 B1 there is known a piezoceramic acceleration recorder which comprises a box-like two-part housing of glass or ceramic in which there is formed a hollow space, wherein between the two parts of the housing there is fastened a piezoceramic plate which engages into the hollow space. The piezoceramic plate is provided with electrodes in the edge corner region which serves for fastening between the housing halves, wherein the housing halves have metallisations for connecting the electrodes with contact connection locations to an electrical circuit.